The present invention relates to devices and methods for using cannulae and the like and, more particularly, to an insertion aid for inserting a cannula of a catheter head into organic tissue, in particular a catheter head for administering a liquid active substance.
Such catheter heads are used in conjunction with infusion devices, for example, so that a patient to whom a fluid is to be administered continuously or repeatedly does not need to have his or her skin repeatedly punctured. Part of the catheter head remains on the patient, namely a cannula housing together with the cannula protruding from it. Another part of the catheter head, having a connection element with a fluid conduit, can be detached from and reconnected to the cannula housing. By means of the connection element, an injection device or an infusion device can be repeatedly attached to the cannula housing and removed from it again, for example in order to exchange a container of fluid or to perform other maneuvers on the injection device or the infusion device. Such a catheter head can also be used, for example, to withdraw analysis fluid from a patient's body or to pass the analysis fluid into and back out of the body. The catheter head usually has a soft cannula which extends into the tissue and which in most cases cannot be introduced into the body without a stabilizing insertion aid. In particular, a soft cannula has to be guided and stabilized in order to puncture the outer layers of skin.
To guide and stabilize the soft cannula of the catheter head, an insertion aid is known which has a guide needle to be pushed into the soft cannula and which can be removed and disposed of after the catheter head is anchored in or on the body or the organic tissue. To exclude any risk of injury to the person handling the insertion aid when removing and disposing of it, it is expedient to provide the guide needle with a needle guard which can largely prevent direct contact and risk of injury. A device for inserting a catheter head with the aid of a stiffening guide needle is known from WO 00/03757. This device has a guide needle which is anchored on a grip section and which, after removal from the catheter head, can be covered with the aid of a protective device. For this purpose, a shield with a contour in the shape of a segment of a cylinder is folded partially about the needle and is locked in position with the aid of interlocking hooks. The guide needle is thus provided with a protective and shielding enclosure, with the result that the device can be disposed of easily and without danger.